DESCRIPTION OF THE PRIOR ART
There are various situations which involve the application of a decoration, pattern, graphics or the like, referred to hereinafter for the sake of simplicity as decoration, to a generally conical peripheral surface portion of an article. It will be appreciated that the article may not be of a conical configuration throughout but for example may comprise a generally cylindrical portion and a conical portion, with the decoration having to be applied to the latter. One way of applying a decoration to a generally conical peripheral surface portion of such an article is to use a stamping foil, which can also be referred to as an embossing or transfer foil, for example a hot stamping foil. In one form of such a method, as is to be found in DE 39 31 556 C2, the foils which are successively provided with a plurality of said decorations are unwound from a supply roll and fed to a stamping station for receiving a respective article to be decorated. In that station the decoration is transferred from the foil on to the surface portion of the article by means of a stamping or applicator roller, referred to herein for the sake of simplicity as a stamping roller, having a cylindrical peripheral surface and being drivable by a suitable drive. The foil is guided around a direction-changing roller which is combined with the supply roll and which is disposed upstream of the stamping station in the direction of forward advance movement of the foil. From the direction-changing roller the foil is passed to the stamping station, with the direction-changing roller being displaced into a position which is suitably adapted to the rotary angular position of the respective article to which a decoration is to be applied from a foil.
In that method, the direction-changing roller is continuously linearly moved by a distance which corresponds to the respective difference between the linear path of movement of the stamping foil and the arc in respect of development of the conical peripheral surface of the article to be decorated, while at the same time the direction-changing roller is continuously pivoted in such a way as to compensate for the linear movement of the stamping foil in relation to the respective aperture angle of the arcuate development of the conical peripheral surface of the respective article. In a suitable form of apparatus for carrying out that method, the direction-changing roller is mounted on a mounting member rotatably about its longitudinal axis, while the mounting member is in turn connected by means of a pivot spindle to an adjusting platform. The platform is arranged for linear movement on a stationary base member, by means of a drive device, the mounting member having a sensing element guided slidably on a guide arrangement provided on the stationary base member. That design configuration therefore involves a number of structural members which slidably co-operate with each other and which therefore each involve a high degree of mechanical wear. The manufacture of all those individual components also means that the apparatus is costly.
Furthermore, in a stamping foil feed apparatus for a stamping machine, as is to be found in German published specification (DE-AS) No 27 21 908, which involves applying decoration by means of a stamping foil to a peripheral surface, in the form of a truncated pyramid, of an article which may be for example the casing of a television, the stamping foil is supplied from a supply roll which is displaceable axially and approximately parallel to the stamping or applicator roller of the stamping station. Between the supply roll and the stamping roller, prior to being applied to the corresponding surface of the article to be decorated, the stamping foil is guided over a guide roller which is displaceable approximately parallel to itself for tensioning the stamping foil and mounted rotatably about a transverse axis extending perpendicularly to the surface to be decorated, of the article. To produce that movement of the stamping foil as it passes from the supply roll to the stamping roller, the guide roller around which the stamping foil is passed and which is movable with the supply roll for the stamping foil can be in the form of a dancer roller, that is to say a roller which is freely movably mounted and which adapts itself automatically stepwise to the respective conditions of operation as governed by the stamping foil and the respective surface of the article to be decorated. The dancer roller will thus move in response to the varying tension produced in the stamping foil by virtue of the fact that the article to be decorated in this case has a plurality of flat surface portions, as it is of a truncated pyramid shape. The situation however is different when dealing with articles which have a conical peripheral surface, for example when dealing with articles of a frustoconical configuration. Such articles include for example cans for liquids or the like.
In a method of laterally guiding a moving web of material along a part of the path of movement thereof, as is to be found in German laid-open application (DE-OS) No 20 06 571, the web passes over a main web guide roller which can be pivoted in a plane of movement out of a neutral position in which the main web guide roller is oriented perpendicularly to the desired path of movement of the web. The lateral position of the web as it passes on to the main web guide roller is sensed at a sensing location upstream of the guide roller. The main web guide roller is pivoted out of its neutral position in such a direction that the deviation of the web from its desired path of movement is then suitably corrected. The web as it runs off the main web guide roller undergoes a change in direction as it passes over a discharge web guide roller and it runs off the latter at a location which is adjacent to a plane through the sensing location and perpendicular to the plane of movement of the main web guide roller. The discharge web guide roller is held parallel to the main web guide roller during the pivotal movement of the latter.
Finally, an apparatus for helically winding material in strip form around an article of a cylindrical or frustoconical configuration is disclosed in UK patent specification No 1 282 588.